# Lithium Oxide Formula

## Lithium Oxide Formula in Detail

This article mainly deals with the chemical formula of lithium oxide, the structural lithium oxide formula with its properties and uses. Lithium oxide is a white solid inorganic compound that is produced when lithium peroxide is decomposed at a temperature of 200 - 300 $^{0}$C. Also when the lithium metal is burnt in the air mixed with oxygen, lithium oxide is formed with small traces of lithium peroxide. Pure lithium oxide is also formed when lithium peroxide is decomposed at 450 $^{0}$C. Thus the chemical formula of lithium oxide is Li$_{2}$O. The other lithium oxide formula is commonly known as lithia or kickerite. It is a highly insoluble but thermally stable form of lithium. The perovskite structured oxides are highly electrically conductive in nature and are therefore widely used in the cathode of solid oxide fuel cells and oxygen generation systems. By analyzing the chemical formula of lithium oxide (Li$_{2}$O), it is clear that the bond shared between the two atoms of lithium and one atom of oxygen is ionic in nature as lithium being a metal of group 1 is highly electropositive while oxygen being group 16 element is highly electronegative in nature. Thus lithium [1s$^{2}$2s$^{1}$] has one valence electron in its outermost shell that is readily available to be donated to form a Li$^{+1}$ ion. And oxygen [1s$^{2}$ 2s$^{2}$ 2p$^{4}$] can readily gain 2 electrons to complete its octane and form O$^{2-}$ ion. Thus in Li$_{2}$O, two lithium-ions donate their outer shell electrons to oxygen that accepts two donated electrons to complete the utmost 2p subshell. Thus the ionic formula of lithium oxide will be 2[Li$^{+}$][O$^{2-}$]. This can be illustrated by the lewis dot structure of lithium oxide.

### Lithium Oxide Structure

From the lithium oxide chemical formula (Li$_{2}$O) it has been observed that in the solid state, lithium oxides adopt an antifluorite structure that is relatable to calcium fluorite. Here in the calcium fluorite structure, the fluorine atoms are replaced with the lithium atoms, and the calcium atom is replaced by an oxygen atom. Thus the lithium oxide chemical formula demonstrates the four coordinated lithium ions [Li$^{+}$] as centers with eight coordinated oxides around the centers. In the ground state gaseous phase, lithium oxide shows a linear bond that is established on the basis of the strong electrostatic force of attraction between the atoms that are ionic in nature. According to the VESPER theory, the shape of the lithium oxide is bent which is similar to that of the water molecule. By the conventional electric deflection method, it has been found that the lithium oxide is non-polar in nature therefore the equilibrium bond angle between lithium and oxygen atoms is near about 180$^{0}$. According to the lithium oxide ionic formula, the coordinate geometry of lithium-ion [Li$^{2+}$] is tetrahedral whereas the oxygen ion [O$^{2-}$] is cubic in nature. The structural representation of the lithium oxide chemical formula is illustrated below.

The alternative schematic representation of the lithium-oxygen formula as a ball and stick model of their single unit cell is also illustrated below for a more clear understanding.

### Lithium Oxide Properties

Lithium oxide is a white crystalline solid and the lithium oxide molar mass is equal to 29.88 g/mol. It has a density that is measured as 2.013 g/cm$^{3}$. It is a strong base with a pH value that is measured as 9.28, also known as log value, and is highly soluble in water and whenever it comes in contact with water while dissolving it reacts vigorously to form lithium hydroxide [LiOH]. It has a very high melting and boiling point. So the boiling point of lithium oxide is measured to be 2600 $^{0}$C whereas its melting point comes around 1438 $^{0}$C. It has an antifluorite structure with tetrahedral and cubical coordinate geometry for lithium and oxygen ions respectively. It has a refractive index measured at 1.644. It has a heat capacity of 1.8105 J/g K or 54.1 J/mol K. the standard molar entropy and the standard enthalpy of formation is measured as 37.88 J/mol K and -595.8 KJ/mol respectively with Gibbs free energy equals -562.1 KJ/mol.

### Lithium Oxide Uses

1. Lithium oxide when combined with copper exerts blue color and when mixed with cobalt generates pink color and therefore it is vastly used for the glazing of ceramics. But as lithium oxide reacts vigorously in water, therefore, it must be kept isolated from water.

2. In a thermal barrier coating system, lithium oxide is used for the evaluation of non-destructive emission spectroscopy as well as degradation monitoring in the system.

3. It is also added as a co-dopant with yttrium oxide which is a white solid and air-stable in nature also known as yttria as a topcoat for ceramic as it does not decrease easily and is therefore considered as a topcoat that sustains for a longer period of time.

4. At a very high heat lithium oxide emits a very definite pattern that is easily detectable and as the intensity of it increases the coating of lithium oxide decreases. But because of its spectroscopic nature of patter, its implantation allows the situ monitoring system thus enabling them to accurately predict the lifetime unless any major failure is involved.

5. It is used as a coolant in many nuclear plants and as a thickening agent to bring a certain consistency in greases.